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Antonis Loizou (some slides created by Paul Groth) VU University Amsterdam LDBC TUC Meeting.

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Presentation on theme: "Antonis Loizou (some slides created by Paul Groth) VU University Amsterdam LDBC TUC Meeting."— Presentation transcript:

1 Antonis Loizou (some slides created by Paul Groth) VU University Amsterdam LDBC TUC Meeting

2 Consortium

3 Associate Partners

4 We are all doing this many times…… Pfizer AZGSKMerckn The Problem

5 ChEMBL DrugBank Gene Ontology Wikipathways UniProt ChemSpider UMLS ConceptWiki ChEBI TrialTrove GVKBio GeneGo TR Integrity “Find me compounds that inhibit targets in NFkB pathway assayed in only functional assays with a potency <1 μM” “Let me compare MW, logP and PSA for known oxidoreductase inhibitors” “What is the selectivity profile of known p38 inhibitors?”

6 Research Questions 6 NumbersumNr of 1Question All oxido,reductase inhibitors active <100nM in both human and mouse Given compound X, what is its predicted secondary pharmacology? What are the on and off,target safety concerns for a compound? What is the evidence and how reliable is that evidence (journal impact factor, KOL) for findings associated with a compound? Given a target find me all actives against that target. Find/predict polypharmacology of actives. Determine ADMET profile of actives For a given interaction profile, give me compounds similar to it The current Factor Xa lead series is characterised by substructure X. Retrieve all bioactivity data in serine protease assays for molecules that contain substructure X Retrieve all experimental and clinical data for a given list of compounds defined by their chemical structure (with options to match stereochemistry or not) A project is considering Protein Kinase C Alpha (PRKCA) as a target. What are all the compounds known to modulate the target directly? What are the compounds that may modulate the target directly? i.e. return all cmpds active in assays where the resolution is at least at the level of the target family (i.e. PKC) both from structured assay databases and the literature Give me all active compounds on a given target with the relevant assay data Give me the compound(s) which hit most specifically the multiple targets in a given pathway (disease) Identify all known protein-protein interaction inhibitors

7 Semantic Resources – Data sets 814,535,923 triples, 569 predicates

8 Semantic Resources – Data sets 8

9 9

10 Semantic Resources - Mappings 18 Million Mappings

11 Semantic resources - Summary Types of semantic resources – RDF Datasets – Mappings – Vocabularies Mesh, UMLS, NCIM – Hierarchies are essential e.g. ChEBI, Enzyme classification rdfs:subClassOf reasoning is essential

12 Data Integration Global – as – View – Flexible global schema defined by domain experts. – Simple, as flat as possible, result structures. Load data into RDF store – A named graph for each dataset. – Inferred triples computed offline and asserted directly.

13 Data Integration Define use cases and view templates – View templates: Required and optional information – Domain experts trust some datasets over others for specific properties. – Results without a core set of properties are meaningless. The rest are optional. – Integration in OpenPHACTS amounts to collating trusted information from the available sources. Convert view templates to SPARQL queries – CONSTRUCT for projection onto global view – Preserve provenance through void:inDataset

14 Linked Data API No public SPARQL endpoint is available for OpenPHACTS – Writing good SPARQL queries has a steep learning curve – Queries that are not well formed can cause instability. Instead SPARQL queries are embedded into Linked Data API (LDA) endpoints. – Enables API developers to fine tune query performance. – RESTful – Multiple formats (JSON, Turtle, TSV, XML and more) – Pagination – HTTP parameters are mapped to RDF properties and SPARQL variables Ability to specify elaborate filtering and sorting conditions – Two-level caching of URLs served Raw RDF results and formatted w.r.t. the “_format” parameter

15 Linked Data API First public release today! – – LDA: – PHP Implementation (Puelia): – OpenPHACTS Extension: https://github.com/openphacts/OPS_LinkedDataApi https://github.com/openphacts/OPS_LinkedDataApi

16 Identity Mapping Service (IMS) Instance level mappings are held externally to the RDF store Driven by Uni. Manchester – Injected into queries at run-time. Better performance (when co-located). Provision of flexible mappings: Scientific lenses.

17 Identity Resolution Service (IRS) text – to – URI functionality Driven by ConceptWiki – Manually curated (sub)String search is performed externally to the RDF store.

18 OpenPHACTS architecture

19 Optimising SPARQL query performance Syntactic variations of the same query vary wildly in evaluation cost. – Pérez Jorge, Marcelo Arenas, and Claudio Gutierrez. Semantics and complexity of SPARQL. ACM Transactions on Database Systems (TODS) 34, no. 3 (2009): 16. Evaluated the utility of 5 heuristics: 1.Minimise OPTIONAL patterns 2.Use named GRAPHs to localise patterns 3.Replace connected triple patterns with sequence paths 4.Use aggregates to reduce the effects of cartesian products. 5.Compare the performance of different syntax for specifying alternative URIs Antonis Loizou and Paul Groth, On the Formulation of Performant SPARQL Queries. Preprint:

20 1&2: Compound Pharmacology

21 1&2: Compound Information

22 1&2: Target Pharmacology

23 1&2: Target Information

24 3: Sequence paths

25 5: Specifying 10 alternative URIs

26 5: Specifying 20 alternative URIs

27 5: Specifying 50 alternative URIs

28 Performance overview: Method# of resultsTime (s) Compound Pharmacology Compound Information Compound Count Datapoints Target Pharmacology Target Information [1.56, ] Target Count Datapoints Enzyme Class Pharmacology ChEBI Class Pharmacology

29 Lessons learnt: Invest in hardware - Develop environment – 400GB RAM, 1.5TB SSD, GHz. Not all RDF stores are created equal Not all RDF datasets are created equal Not all SPARQL queries are created equal. Perfomance is a function of: – SPARQL syntax – Dataset schema – Data size – Loading strategy/named GRAPHs – RDF store

30 Open PHACTS Information Publications – Overview paper: Williams, A.J., Harland, L., Groth, P., Pettifer, S., Chichester, C., Willighagen, E.L., Evelo, C.T., Blomberg, N., Ecker, G., Goble, C., Mons, B.: Open PHACTS: Semantic interoperability for drug discovery. Drug Discovery Today. 17, 1188–1198 (2012). – Technical approach: Gray, A.J.G., Groth, P., Loizou, A., et al.: Applying linked data approaches to pharmacology: Architectural decisions and implementation. Semantic Web. (2012). – SPARQL heuristics: Antonis Loizou and Paul Groth, On the Formulation of Performant SPARQL Queries. Preprint:


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